The swedish royal ladies wear beautiful hair combs for evening occasions (for example, there are 2 beautiful diamond and sapphires haircombs in the Leuchtenberg parure). Usually they wear them when they have their hair up. Maybe Queen Elizabeth has never worn them because she has shorter hair and always the same hairstyle.

I thought they were hairpins

QEII doesn't seem to favor amethysts in general, so it may be more than just hairstyle.

Yes you are right, those in the Leuchtemberg parure hare hairpins, not haircombs, sorry for my bad english!
What I meant is that the swedish ladies have worn hairpins, haircombs and even brooches in their hair.
I think you are right, Queen Elizabeth doesn't favor amethysts, but I think it doesn't depend only on the stone. I'm sure that in her vaults there are many haircombs and hairpins from previous generations that she could wear. Maybe she doesn't like that kind of jewels or they don't go well with her hairstyle.
I think that the only time she has worn something in her hair (excluding tiaras) is when she has worn the ears of wheat brooches.

The Queen wore an interesting brooch for today's reception, which personally I had never seen before.
It appears to have a filigree design with 10+ small diamonds across the centre.

Anyone any idea on this brooch? Or have we finally witnessed a genuinely new addition to Her Majesty's collection?
It kind of reminds me of a brooch I've seen of Elizabeth I's portrait; at least, the design is quite similar, although there are marked differences too.

Cropped from larger image and constitutes less than 20% of the original.

The Queen wore an interesting brooch for today's reception, which personally I had never seen before.
It appears to have a filigree design with 10+ small diamonds across the centre.

Anyone any idea on this brooch? Or have we finally witnessed a genuinely new addition to Her Majesty's collection?
It kind of reminds me of a brooch I've seen of Elizabeth I's portrait; at least, the design is quite similar, although there are marked differences too.

Cropped from larger image and constitutes less than 20% of the original.

All I thought was WOW when I saw this!

Granted I like HM in far more gram weight - but the work on the brooch seems to be exquisite! It is not to my taste - but I am still floored by the detailed work and design. Lovely work. Kudos to whomever - it is new and I like it IMHO.